Google Retooling the Android Market

Speaking at an event in San Francisco, Google group manager for Android platform Eric Chu said that it is working on changes to the Android Market that it hopes will boost developers' interest in the market as well as improve the end user experience. The Android Market has yet to officially support in-app purchases, and though this feature was supposed to debut in 2010, it has yet to appear. Google says this feature is coming soon. Google is also working with more network operators to enable carrier billing. Right now, only AT&T and T-Mobile USA in the U.S. support carrier billing. Sprint and Verizon Android users must use a credit card to purchase apps. Google also said it is hoping to improve app discovery in the Market by refining app classifications, improving search, and adjusting how apps are ranked. Google didn't provide specifics on when these changes might be integrated into the market.

That is how it is done in Blackberry App World, after you hit 'purchase' you have to enter a username and password to confirm the purchase. I would be surprised if it was different for the Android Marketplace.